Method for protocol data unit (pdu) session anchor relocation and 5g network registration

Abstract

Provided is a method of relocating a session and service continuity (SSC) mode 2 protocol data unit (PDU) session anchor by a session management function (SMF) device, the method including determining a relocation of a PDU session anchor; releasing a PDU session associated with an old PDU session anchor by sending, to a user equipment (UE), N1 SM information including a PDU session release command message through an access and mobility management function (AMF) device; and selecting a new PDU session anchor to establish a PDU session associated with the new PDU session anchor.

What is claimed is: 
     
         1 . A method of relocating a session and service continuity (SSC) mode 2 protocol data unit (PDU) session anchor by a session management function (SMF) device, the method comprising:
 determining a relocation of a PDU session anchor;   releasing a PDU session associated with an old PDU session anchor by sending, to a user equipment (UE), N1 SM information that includes a PDU session release command message through an access and mobility management function (AMF) device; and   selecting a new PDU session anchor to establish a PDU session associated with the new PDU session.   
     
     
         2 . The method of  claim 1 , wherein the PDU session release command message includes a PDU session ID that needs to be relocated. 
     
     
         3 . A method of relocating a session and service continuity (SSC) mode 3 protocol data unit (PDU) session anchor by a session management function (SMF) device, the method comprising:
 determining a relocation of a PDU session anchor;   sending, to an access and mobility management function (AMF) device, Namf_Communication_N1N2MessageTransfer that includes a PDU session ID indicating a PDU session to be relocated; and   releasing a PDU session associated with an old PDU session anchor after establishment of a PDU session between a user equipment (UE) and a new PDU session anchor.   
     
     
         4 . The method of  claim 3 , wherein the Namf_Communication_N1N2MessageTransfer includes a cause indicating that a PDU session re-establishment in the same data network is required and information regarding whether the SMF device needs to be reallocated. 
     
     
         5 . The method of  claim 3 , wherein the old PDU session anchor releases an old PDU session using the UE before expiry of a timer indicating a time in which the old PDU session is maintained or releases the old PDU session using the SMF device until the timer expires. 
     
     
         6 . A method of relocating a session and service continuity (SSC) mode 3 protocol data unit (PDU) session anchor by an access and mobility management function (AMF) device, the method comprising:
 receiving Namf_Communication_N1N2MessageTransfer that includes a PDU session ID indicating a PDU that needs to be relocated in response to a session management function (SMF) device determining a relocation of a PDU session anchor from an old PUD session anchor to a new PDU session anchor; and   sending, to a user equipment (UE), a PDU session modification command message that includes a cause indicating that a PDU session re-establishment in the same data network is required and a time in which a PDU session is maintained.   
     
     
         7 . The method of  claim 6 , wherein the Namf_Communication_N1N2MessageTransfer includes information regarding whether the SMF device needs to be reallocated. 
     
     
         8 . The method of  claim 6 , wherein the old PDU session anchor releases an old PDU session using the UE before expiry of a timer indicating a time in which the old PDU session is maintained or releases the old PDU session using the SMF device until the timer expires.